Section 402. Summons; time to appear and answer

(a) If the summons is
  personally delivered to the defendant within the city of  New  York,  it
  shall  require  him  to  appear  and answer within twenty days after its
  service.
    (b) If the summons is served by any means other than personal delivery
  to the defendant within the city of New York, it shall provide that  the
  defendant  must  appear  and  answer  within  thirty days after proof of
  service is filed with the clerk.